In the art of article handling, various types of sorting switches have been provided heretofore. For example, switches have been provided for receiving articles from two or more input conveyors and for converging the articles, so that all the articles are directed to a single output conveyor. Other switches have been designed to receive articles from a single input conveyor and to divert the articles so that the articles are selectively directed to one of two or more output conveyors. Still other sorting switches have operated to receive articles from a pair of input conveyors and to direct articles to a pair of corresponding output conveyors while selectively combining certain articles by directing them to a third output conveyor.
In an attempt to provide a single sorting switch capable of performing many of the functions of the aforementioned switches, the switch described and claimed in U.S. Pat. No. 3,987,888, issued Oct. 26, 1976 to I. E. Wickam and assigned to the assignee hereof, was developed. This switch is capable of receiving articles from two input conveyors and selectively directing the articles to either of two output conveyors and therefore constitutes an important contribution to the art of sorting switches. In Wickam, a plurality of pallets are mounted for movement around a course including an upper sorting portion and a lower return portion. The upper sorting portion of the course defines a pair of parallel article conveying paths, and alternate sets of pallets are normally aligned with opposite article sorting paths. Switching of an article from one conveying path to the other can only be accomplished by the lateral movement of the set of pallets on which the article is supported. Since delivery of the articles to the sorting switch must coincide with the alternate positioning of the sets of pallets, the sorting switch of Wickam requires sensing or timing means associated with the input conveyors to deliver each article to a set of pallets on the sorting switch.
The present invention provides numerous advantages in addition to those of the sorting switches of the prior art. For example, one such advantage is that it is unnecessary to deliver articles to the sorting switch of the present invention in a particular sequence when the device is operated in the straight through mode. Another advantage is that the present invention provides a sorting switch capable of use with articles of varying sizes and shapes. Still another advantage of the present invention is the substantial increase in its transporting capacity in terms of the quantity and weight of articles handled thereby. These and other advantages deriving from the use of the invention will readily suggest themselves to those skilled in the art.
In accordance with the broader aspects of the invention, a plurality of pallets are mounted for movement around a course including an upper sorting portion and a lower return portion. The upper sorting portion of the course defines a pair of parallel article conveying paths, and the pallents are normally aligned, in alternating sequence, with opposite article sorting paths. Switch apparatus is provided for selectively allowing a predetermined pallet to follow its normal article sorting path or for diverting the pallet into alignment with the opposite article sorting path. Structure is provided on the return portion of the course for returning all the pallets to their normal orientation relative to the course.
In accordance with more specific aspects of the invention, the pallets are slidably supported on a pair of tubular pallet support members. Each pallet has a switch engaging member depending therefrom. The structure for returning the pallets to their normal orientation relative to the course comprises camming apparatus which engages the switch engaging members of the pallets during movement thereof along the return portion of the course.
The switching apparatus comprises a pair of switching mechanisms mounted on opposite sides of the upper article sorting portion of the course. Each switching mechanism includes a stationary input channel for receiving the switch engaging member of the pallet aligned with one of the article conveying paths. The input channel directs the switch engaging members to a switching channel which is mounted for pivotal movement between a position in which the switch engaging members and the pallets connected thereto are directed along the normal article conveying path and a position in which the switch engaging members and the pallets connected thereto are diverted to the opposite article conveying path. The input channel and the switching channel of each switching mechanism are so arranged that the adjacent ends thereof are aligned regardless of the positioning of the switching channel. Camming structure is provided for receiving the switch engaging members from the switching channel and for directing the switch engaging members and the pallets connected thereto either along the normal article conveying path or into alignment with the opposite article conveying path.